Mechanical piano-player and like instrument.



W. H. GRIMSDALB, MECHANICAL PIANO PLAYER AND LIKE INSTRUMENT.

APPLICATION FILED OCT. 31, 1912.

Patented Mar. 10, 191 i five x257 20 keys are actuated.

' To all whom it may concern Be it known that I,

UNITED STATES PATENT OFFICE.

WILLIAM HENRY GRIMSDALE,

OF TWICKENHAM, ENGLAND, ASSIGNOR TO GRIMS- DALES PATENTS ILIMITED, OFLONDON, ENGLAND.

' nism the strength with which the several keys of the piano or the likeare struck corresponds with the areas respectively of the air passagesthrough the music sheet into the tracker bar apertures, through. whichthe In the British Specification No. 4942 of 1908, I have described theapplication of dampin devices whereby the varying areas of the airpassages through the music sheet are made effective in producing"varying strengths of blow on the keys of the piano or the like, saiddamping devices consisting for each note of a variable capacity chamberor damping pneumatic mechanically connected to the stri connected to anaperture in the tracker board, the usual aperture being also provided inthe tracker bar for the purpose of actuating the key striking pneumaticthrough" relays in the usual manner; The trackerbar aperture which isconnected to the damping pneumatic is placed just in front of-the usualaperture, so that a perforation of the music sheet traveling over thetracker bar first opens the'aperture in connection with a dampingpneumatic, and be.- fore this is closed, opens the aperture operatingthe key striking mechanism. Asthe striking pneumatic collapses, itextends the damping pneumatic, which draws air in through the trackerbar aperture connected therewith, a perforation of large area allowingthe damping pneumatic to extend more easily than a. small perforation,and thus varying the'strength of blow on the key. I have found that thismethod of varying the strength of the blow on the key is satisfactory,provided the size and pitch of the tracker bar apertures are such as toallow Specification of Letters Patent.

Application filed dctober 31,1912. Serial No. 728,826.

ing pneumatic and pneumatically MECHANICAL PIANQ-PLAYER AND LIKEINSTRUMENT.

Patented Mar. 10,1914.

for perforations in the'music sheet, having perforations in the musicsheet.

The invention consists in providing an air chamber in pneumaticconnection with the damping pneumatic, such chamber being provided witha valve operated pneumatically from the tracker bar, and when openedadapted to connect the damping pneumatic through the chamber with theatmosphere.

The invention further consists in provid-' ing an air chamber inpneumatic connection with the damping pneumatic, and having an apertureto atmosphere, on the outside of which is a valve operated by apneumatic in the chamber, such pneumatic being connectfed to the dampingaperture in the tracker bar, a bleed hole being provided leading fromthe passage connecting the pneumatic and tracker bar into the air'chamber.

The invention further consists in providing each damping pneumatic witha valve opening to atmosphere, and controlled by hand, so that theretarding 'efi'ect of the damping pneumatic can .be varied as desired.The control of the hand operating valve niay be separate for each note,or groups of notes, or a single control may be used for all thenotes,-as desired.

Referring .to the accompanying drawings-Figure 1 is a section ofmechanism for actuating one of the keys of the piano; Fig. 2 is a planshowing a hand-control; and Fig. 3 shows a portion of the music sheetused with the apparatus.

In the form of the invention shown in the figures the tracker bar a isprovided with the usual apertures 6 leading to *the pneumatics 0, d,controlling the strikin pnoumatics e, and in close proximity and infront of each of the apertures b in the tracker bar is an aperture fleading to the pneumatic g, which controls the valve h bywhich air canbe admitted through an air chamber A to the damping pneumatic Z on thecorrespondingnote-playing pneumatic c. The damping pneumatic Z. may beprovided with an outwardly opening flap valve m to allow quick variablyadmit air to open the valves 72. when it is desired to sound a loudernote independently of' the size of the perforation over the aperture f.If the pneumatics g and the valves h are correctly proportioned the liftof the valves Ii vTill vary with the variation of the opening of theapertures 0 in the bar 9%,

resulting with small perforations over theapertures f in variation ofthe strength of notes to any degree from the softest to. the loudest.

The action of the apparatus is as follows:-With a narrow perforationover the damping aperture f, when the key-striking pneumatic e isactuated, the damping pneumatic Z is extended, and forms a vacuum .orpartial vacuum in the air chamber k. There is also a small pressure inthe pneumatic g in the air chamber, because owing to the smallperforation over the aperture, the air in this pneumatic is exhaustedthrough the bleed hole 9 as fast as it enters from the tracker .bar f,and consequentlythere is not sufiicient thrust on the'valve k to open itagainst the pressure of the atmosphere,

which tends to keep it closed. It follows therefore that the only way inwhich air;

can enter the damping pneumatic Z is through the perforation and trackerbar aperture f and through the bleed hole 9 in series with it, resultingin a large amount of resistance to the extension of. the dampingpneumatic Z, so that a soft note is produced. If, however, there is awider perforation over the damping aperture f, the pressure in thepneumatic g situated 1n the air chamber will be greater, and the bleedhole 9 can he so proportioned that the pressure in the pneumatlc will besuflicient to open the valve it against .the atmospheric pressure, andso open the damping pneumatic direct to atmosphere, with the result thatthere is a small resistance to the extension of the damping pneumatic,and a loud note is produced. a

By providing a bleed hole g of suitable size, sufiicient pressure can beattained in the pneumatic g to open the valve h to atmosphere by a 'verysmall increase in width of the perforation. It is desirable but notnecessary to provide an adjustable v bleed hole, so that each note canbe adjusted individually. I "It will be readily seen that by opening,partially closing or closing the manually controlled valves leading tothe damping pneumatics Z, or the apertures in the bar '22, the operator,when playing, 1 can render notes represented by narrow perforations withany degree of strength between the softest and loudest notes, so thatfor instance in playing a piece of music in which the air or melody isrepresented by wide perforations, and the accompaniment notes by narrowperforations, it is possible to vary the-latter to any degree betweenthe softest and loudest notes.

' Having now described my invention, what I claim as new and desire tosecure by Letters Patent is 1. In a mechanical player, in combination, astriking pneumatic for causing a note to be sounded, a variable capacitychamber connected to said striking pneumatic, an air chamber incommunication with said variable capacity chamber, an opening leadingfrom said' air chamber to atmosphere, a valve controlling said opening,a tracker bar, two apertures in said tracker bar for each note, saidapertures being in the line of travel of the music sheet, a vacuumchamber, a valve between said striking pneumatic and said vacuumchamber, a pneumatic controlling said valve, one of the said aperturesin said tracker bar being in communication with said pneumaticcontrolling said last mentioned valve, means for controlling saidopening and a passage from said second aperture in said tracker bar to,said controlling means as set forth.

2. In a mechanical piano player, in combination, striking. pneumaticsfor causin a note to be sounded, a variable capacity chamber connectedto each of said striking pneumatics, an air chamber in communicationwith said variable capacity chamber, an' opening leadin from each ofsaid air chambers to atmosp ere, a valve controlling one of saidopenings, a tracker bar, apertures in said tracker bar, a pneumatic insaid air o chamber controlling said valve, and a pas sage leading fromsaid apertures in said pneumatic 1n said air tracker bar to saidchamber, as set forth.

3. In a mechanical piano player, in combination, striking pneumatics forcausing a note to be sounded, a variable capacity chamberconnected toeach of said striking pneumatics, an air chamber in communication withsaid variable capacity. chamber,

an opening leading from each of said air chambers to atmosphere, a valvecontrolling one of said openings, a tracker bar, apertures in saidtracker bar,a pneumatic in said air chamber controlling said valve, a

passage leading from said aperture in said tracker bar to said pneumaticin said air chamber, and a bleed hole leading from iaidhchamber intosaid air chamber, as set ort 4. In a mechanical piano player, incombination a striking pneumatic for causing a note to be sounded, avariablev capacity chamber connected to said striking pneumatic, an airchamber in communication with said Variable capacity chamber, an openingleadingfrom said air chamber to atmosphere, a valve controlling one ofsaid openings, a tracker bar, an aperture in said tracker bar for eachnote, a pneumatic in said air chamber controlling said valve, a passageleading from said aperture in said tracker bar to said pneumatic in saidair chamber, a bar, an aperture for each note in said bar leading tosaid valve actuating 15 WILLIAM HENRY GRIMSDALE.

Witnesses:

BERTRAM H. MA'rrHEws, W. T. SWERTEN.

